endothelial function and cardiovascular prognosis · low carbohydrate diet •previous studies have...
TRANSCRIPT
Endothelial Function and
Cardiovascular Prognosis
David Gutterman, MD FCCP
Senior Associate Dean for Research
Professor of Medicine and Physiology
Medical College of Wisconsin
September 26, 2013
3rd Dubrovnik Cardiology Highlights
Milwaukee Art Museum
Milwaukee, Wisconsin
Green Bay Packers
World Football Champions, 2011
Milwaukee Brewers Baseball
goals1. Detail translational research findings that
showed the potential clinical importance of
endothelial function
2. Show clinical examples of how understanding
endothelial function can alter patient care.
3. Propose new therapies aimed at preventive
detection of, and therapy for, atherosclerosis.
Role of the Endothelium in Managing
Cardiovascular Risk
- Shear Stress from normal blood flow
- Acetylcholine
- Bradykinin{
Vascular Structure-Function Relationship
EDRF
1980: Furchgott identified the
critical role of endothelium in
vasodilation
- Shear Stress from normal blood flow
- Acetylcholine
- Bradykinin{
Vascular Structure-Function Relationship
1980: Furchgott identified the
critical role of endothelium in
vasodilation
1990: Furchgott and others showed
that the dilator compound
released from endothelium is
Nitric Oxide (NO)
1998: Nobel Prize awarded to
Furchgott, Ignarro, and Murad
NO
Physiological Properties of NO
vasodilation
Each of these properties is antiatherogenic
in coronary and systemic vessels
6
inhibit platelet aggregation
induce apoptosis of smooth muscle cells
inhibit the oxidation of LDL cholesterol
prevent smooth muscle proliferation and intimal migration
anti-inflammatory: prevent white cell margination
inhibit leukocyte adhesion to endothelial cells
inhibits cell adhesion molecule expression
Nitric oxide released from the endothelium maintains
vascular integrity and prevents the development of
atherosclerosis
NO Hypothesis
for Atherosclerosis
Corollary: Arteries would become atherosclerotic if not
for nitric oxide being released from the endothelium
Testing NO (2)Testing the NO Hypothesis
1. Risk factors for cardiovascular disease are associated
with endothelial dysfunction and loss of NO
2. Endothelial dysfunction precedes atherosclerosis
3. Improving endothelial function and restoring NO
production prevents or reduces atherosclerosis
4. Endothelial dysfunction portends bad prognosis in
humans
Must show that:
Risk vs endo fctn
Impaired no dilation
Risk Factors and Endothelial Function
Risk for
CAD
Endothelial
Dysfunction
Loss of
NO
Diabetes
HTN
Hypercholesterolemia
Family History of CAD
Tobacco Use
Male Gender
Menopause
Mental Stress
Hyperhomocysteinemia
Endo linkCommon Link between Risk Factors and NO
Risk
Factors
Atherosclerosis
-
NO
SODH2O2
Arginine
NOS
ONOO-O2
ROS NO
Testing NO (2)Testing the NO Hypothesis
1. Endothelial dysfunction with loss of NO is associated
with risk factors for cardiovascular disease
2. Endothelial dysfunction leads to atherosclerosis
3. Improving endothelial function and restoring NO
production leads to improved outcomes
4. Abnormal endothelial function portends bad prognosis
Must show that:
- from Zeiher, Drexler et al., Circulation, 1991
Epicard. Anat:
Dilator
Ach
Cold Pressor
FMD
Endothelial Dysfunction Leads to Atherosclerosis
- 38 patients
N=11 N=9 N=9 N=9
normal CholNon-
Obst.Obst.
CAD
Testing NO (2)Testing the NO Hypothesis
1. Endothelial dysfunction with loss of NO is associated
with risk factors for cardiovascular disease
2. Endothelial dysfunction leads to atherosclerosis
3. Improving endothelial function and restoring NO
production leads to improved outcomes
4. Abnormal endothelial function portends bad prognosis
Must show that:
Cooke morphol.Reversal of Atherosclerosis in
Hypercholesterolemia
- Cooke, et al. JCI, 1992
vehicle L-arginine
- Male rabbits
- 10 weeks HC diet
- Aortic histomorphometry
Treat the pathology of
hypercholesterolemia
without changing the cholesterol!
Intima
Media
Testing NO (2)Testing the NO Hypothesis
1. Endothelial dysfunction with loss of NO is associated
with risk factors for cardiovascular disease
2. Endothelial dysfunction leads to atherosclerosis
3. Improving endothelial function and restoring NO
production leads to improved outcomes
4. Abnormal endothelial function portends bad prognosis
Must show that:
Susan pitt
In Vivo Measurement of Endothelial Function
Patti et al. Circ. 2005
Prognostic Importance of FMD in PCI Patients
Patients: - 136 following PCI for single vessel disease
- FMD 30 days after PCI
- 6 mo. f/u
FMD was the strongest predictor of restenosis (OR 4.5) by multivariate analysis
Impaired no dilation
Prognosis and Endothelial Function
- Schachinger, et al. Circulation, 2000
- 147 consecutive
patients with cath
- -measured
coronary endothelial
function
- 7.7 year follow-up for
cardiovascular events
(MI, UA, death, PCI,
CABG, CVA)
- Endothelial function was
an INDEPENDENT
predictor of prognosis
Impaired no dilation
Prognosis and Endothelial Function
- Bugiardini, et al. Circulation, 2004
-42 women with chest pain + SPECT scans and normal coronary arteries
at cath.
- ~Half showed coronary
constriction to Ach and ~½ showed
dilation at baseline.
-Followed for 10 years with repeat
angiogram.
-At 10 year follow-up:
-None that originally dilated to Ach
developed CAD.
-13/17 who originally constricted to
Ach developed angiographic CAD.
Testing NO (2)Testing the NO Hypothesis
1. Endothelial dysfunction with loss of NO is associated
with risk factors for cardiovascular disease
2. Endothelial dysfunction leads to atherosclerosis
3. Improving endothelial function and restoring NO
production leads to improved outcomes
4. Abnormal endothelial function portends bad prognosis
Must show that:
Are All Forms of Exercise Healthy?
• It has long been known
that aerobic exercise is
healthy.
• What about resistance
exercise like
weightlifting?
Arterial Blood Pressure Responses to Heavy
Resistance Exercise
• Leg Press Exercises
• Peak blood pressure 480/350 mmHg
MacDougall et al. J Appl. Phys. 1985.
Hypothesis
Acute hypertension associated with weight
lifting impairs vascular endothelium-
dependent dilation in humans.
Age (years) 28 ± 2
Sex 5 female, 9 male
BMI 27 ± 2
Resting SBP
(mmHg)124± 4
Brachial Artery
Diameter (mm)4.2 ± 0.2
Baseline FMD (%) 5.6 ± 1.5
Max Pounds Lifted 439 ± 57
Peak Exercise SBP 213 ± 8
Subject Characteristics
Protocol
FMD Exercise FMD
Effect of Weight Lifting on Flow Mediated Dilation
in Conditioned Weight Trainers
Pre exs Post exs
FM
D (
% C
han
ge in
Dia
mete
r)
0
2
4
6
8
10
Age (years) 28 ± 2 33 ± 2
Sex 5 female, 9 male 6 female, 9 male
BMI 27 ± 2 29 ± 2
Resting SBP (mmHg) 124± 4 122 ± 4
Brachial Artery Diameter
(mm)4.2 ± 0.2 4.0 ± 0.2
Baseline FMD (%) 5.6 ± 1.5 7 ± 1.0
Max Pounds Lifted 439 ± 57* 239 ± 27
Peak Exercise SBP 213 ± 8 198 ± 4
Effect of Weight Lifting on Flow Mediated Dilation
in Sedentary Subjects
Pre exs Post exs
FM
D (
% C
han
ge in
Dia
mete
r)
0
2
4
6
8
10
*
Jurva, JACC 2006
Effect of Different Modes of Exercise on
Endothelial Response to Weight Lifting Stress
SED CWL Runner CT
Ab
so
lute
Ch
an
ge i
n B
rach
ial
Art
ery
FM
D (
%)
-4
-2
0
2
*
#†
#†
†
Assessment of
endothelial function
could help optimize
the CV benefit of an
exercise regimen.
Benefit also seen
with other stresses:
hyperglycemia; lipid
bolus
Phillips, preliminary data 2013
blankMethods to Improve Endothelial
Function (NO release) (? and reduce atherosclerosis?)
Exercise Magnesium supplementation
Red Wine, other alcohol LDL apheresis
Grape Juice Nifedipine
Estrogen Replacement Mediterranean diet
Statins thiazolidinediones
ACE-I fish oils, black tea
Arginine supplementation potassium channel antagonists
Folic acid (high dose) Bone-Marrow EPC
Vitamin C, E Dialysis
Targeted Antioxidants Probucol
(SOD3, mitochondria) Apo-A1 mimetics (D-4F)
Sildenafil Caveolin disruption
Novel treatmentsPotential Clinical Utility of Measuring
Endothelial Function
6
Cholesterol
Diabetes
Tobacco
Obesity
FHx
HTN
O-2
L-arginineNOS
NO
“atherostasis”
X
Traditional Treatment
Strategies
Novel Treatment
Strategies
antioxidants
X
NO
substrates
Gene Therapy
Cell Therapy
cofactorsReplacement NO??
blankImplications for Detection of CAD
Disease
Severity
Plaque
rupture
Mature calcified
Plaque
Early non-
obst. Lesion
Pre-
Lesion
ACS
EBCT
Cath
NI image,
Stress test
Endothelial
function
Disease Progression
Reversible Permanent
The EndQuestions?
Dubrovnik, September 26, 2013
shear NO athero
Shear Stress NO Arteriosclerosis
Endothelial Dysfunction Leads to Atherosclerosis
(Shear and Atherosclerosis)
• Athletic amenorrhea is a component of the “Female Athlete
Triad” which consists of disordered eating, amenorrhea of
hypothalamic origin, and osteoporosis.
• The hormone profile of amenorrheic athletes is similar to that
of postmenopausal women.
• Menopause is accompanied by endothelial dysfunction and
accelerated atherosclerotic cardiovascular disease.
• Could amenorrheic athletes be at higher risk for
vascular disease?
The Female Triad: A common finding in
elite women athletes
Hoch et al. MSSE 2003
Effect of Amenorrhea on Endothelial Function in
Women Runners
Am
enorr
heic
s
Olig
om
en.
Eum
en.
15 women in each
group
All ran 25 mi/week
No other baseline
differences
Follow-up Regained Menses - FMD
Initial Testing Follow-up
31 32 33 34 35
Per
cent
Dila
tion
0
2
4
6
8
10
* P=0.016
Female Tetrad may be a
new risk factor for early
atherosclerosis
Effect of Return of Menses on FMD
- 2 year follow up
Dieting
AHA Diet Atkins Diet
Fruits High Low
Vegetables High Low
Carbohydrates High Low
Fats & Oils Low High
Salt Low High
Meat Low High
Low Carbohydrate Diet
• Previous studies have shown…• Similar or better weight reduction vs. low fat diets
• Improvement or no change in lipid profiles
• Similar reduction in blood pressure
• Paradox• Weight loss is good for your health
• Acute excessive intake of high-fat foods is bad for health.
(High fat intake is a risk factor for CAD)
Hypothesis
• By using an equally effective weight reduction
regimen, a traditional low-fat diet will improve
vascular endothelial function while a low-
carbohydrate diet will not.
Materials and Methods
• Inclusion Criteria– Male or female, ages of 18 & 50 years, BMI of 29-39
– Healthy subjects not currently on a diet
• Exclusion Criteria– Any known health problem that impairs endothelial function
(history of CV disease, HTN, elevated cholesterol, etc.)
– For the 11 subjects that have completed the diet, 40+ subjects were screened and eliminated because of exclusion criteria!
• Randomized 6 week diet
- Phillips et al. Hypertension, 2008
Results
CHANGE IN SBP OVER 6 WEEKS
*p=0.048 p=0.062 *p=0.008
100
105
110
115
120
125
130
135
LOW CARB LOW FAT ALL
PR
ES
SU
RE
(m
m H
g)
WEEK 0
WEEK 6
Systolic blood pressure decreased similarly with both diets
Cholesterol did not differ between diets.
Weight loss was similar between diets (~4-5 kg).
Results
Not all diets are the same. Endothelial function may
help identify what works best.
- Phillips et al. Hypertension, 2008
summarySummary
•Nitric oxide, derived from the endothelial enzyme NOS, is a
potent regulator of vasomotor tone in the normal human heart.
•Risk factors enhance oxidative stress, impair conduit vessel
dilation and NO responses, and initiate a pro-atherogenic state.
•Loss of NO appears to be the final common pathway leading to
development of atherosclerosis.
•Novel therapies designed to improve or restore NO
bioavailability should be effective in preventing and reversing
atherosclerosis and its complications.
Antiox athero seconAntioxidants and Atherosclerosis
Study Year Subjects
(n)
F/U(yrs)
Tx Result
CHAOS 1996 2002 2 Vit E +
Azen et al. 1996 146 Vit E +
CARET 1996 18314 12 ß-carotene -
MPV 1997 317 0.6 Vit E+C -
PART 1997 101 0.6 Probucol +
ATBC 1997 1862 3-5 ß-carotene -
Secondary Prevention: Clinical Trials
Antiox athero primAntioxidants and Atherosclerosis
Study Year Subjects
(n)
F/U(yrs)
Tx Result
NHANES 1992 11348 10 Vit C +
Nurse Health Study 1993 87245 8 Vit C -
Health Prof. Study 1993 39910 4 Vit E +
LRC-CPPT 1994 1899 13 ß-carotene +
Gale et al. 1995 730 20 Vit C +
Iowa Women Health 1996 34486 7 Vit E +
Rotterdam Study 1999 4802 4 Vit C -
Knekt et al. 1994 5000 14 Vit E +
Primary Prevention: Epidemiological
Folate endo rabelinkFolate and Endothelial Function
- Verhaar, et al. Circ., 1999
Improving the Risk
without changing the
risk factor
20 subjects with FH
20 controls
Treat with folate for
one month
Assess endothelial
function
Prognosis: FMD vs. IMT
- 398 consecutive patients undergoing cath
- Stratified by FMD >7.6% or <7.6%
- Followed 5 years for patients with CAD
- Events: MI, Death, hospitalization for
worsening angina, repeat angiography for
angina Frick et al. JACC 2005
Single measure of FMD
vs. sequential
Prog and endo fctn
Impaired no dilation
Prognosis and Endothelial Function(outcomes (death, MI, CVA) following an improvement in endothelial function)
- Fichtlscherer, et al. Circ, 2004
Ach (FBF) SNP (FBF)
Results: Post-Nitroglycerin
Administration
There were nodifferences in NTG-induced dilation forsubjects on both dietsover 6 weeks.
NTG-MEDIATED DILATIONS OVER 6 WEEKS
23.56%
20.68% 19.27%20.14%
23.49%
17.33%
0%
5%
10%
15%
20%
25%
30%
LOW FAT LOW CARB
PE
RC
EN
T (
%)
WEEK 0
WEEK 2
WEEK 6
Goal: Reduce death rate from coronary heart disease and stroke by 25%
· 23.1% reduction in death rate from coronary heart disease
· 19.1% reduction in death rate from stroke
Goal: Reduce prevalence of tobacco use, high blood cholesterol and
physical inactivity by 25%
· 20.0% reduction in prevalence of high cholesterol
· 12.9% reduction in prevalence of tobacco use
· 2.5% reduction in those not engaged in moderate or vigorous
physical activity
Goal: Reduce rate of uncontrolled high blood pressure by 25%
· 8.5% reduction in uncontrolled high blood pressure
Goal: Eliminate the growth of obesity and diabetes (Goal: 0% rate of
growth)
· 1.39% rate of growth in obesity
· .28% rate of growth in diabetes (no new data since baseline)
AHA 2007 Goals and Results
TREND quinaprilQuinapril and Endothelial Function
- Treasure, NEJM 1995
-TREND (Trial on
Endothelial
Dysfunction)
-Pts. with CAD but
without HTN,
CHF, or high Chol.
-6 month f/u cath
Stem Cells and Endothelial Function
Higashi et al. Circ 2004
45 patients with
CAD; 15 controls
Vasa et al. Circ Res 2001 7 patients with
PVD; autologous
BM stem cells
Navab, M. et al. Circulation 2002;105:290-292
Studies in LDL receptor-null mice (LDL R-/-)
ROS and Vasomotor Function
Disease
Severity
Vasodilator
Mechanisms
ROS
Generation
H2O2
ONOO-
superoxide
NOEET
H2O2
Atherogenic
Potential
Endothelial Nitric Oxide Synthase
cNOS
L-Arginine
citrulline
NO
BH4
Ca++
calmodulin
FAD
FMN
caveolin
caveolinCa++
calmodulin
3
Katz, Circulation 2005
Endothelial Function and Prognosis in CHF
Kaplan-Meier plot of survival over time
149 FC II-III CHF subjects,
EF<40%.
Meds stopped the day of FMD
testing.
> median FMD
< median FMD
Takase et al. Circ. J. 2006
Prognostic Equivalence Between Coronary
and Brachial Endothelial Function
Patients: 70 with suspected CAD, no known PVD
Event: MI, Death, readmission for UA.
Patti et al. Circ. 2005
Prognostic Importance of FMD in PCI Patients
Multivariate logistic regression analysis showing that FMD,
diabetes mellitus, and stent diameter <3 mm are independently
associated with significantly increased risk of in-stent restenosis.
Karatzis et al. AJC 2006
Prognostic Importance of FMD in CAD Patients
Kaplan-Meier survival curve for patients with ACS and no ST-
segment elevation. FMD was the strongest independent predictor
of events (CV death, MI, CVA, UA) in multivariate analysis.
Flow-induced Dilation (CAD vs. no CAD)
510 20 100
0
20
40
60
80
100 Control
LNAME
*
*
Control
LNAME
510 20 100
0
20
40
60
80
100
%
max
dilation
Pressure gradient (cmH2O)
* p<0.05
n=5
n.s.
n=6
A. Patients with no CAD B. Patients with CAD
Miura et al. Circulation 2001
Therapeutic Improvement in IMT
Hodis et al. (Ann Int Med) studied 94 adult subjects with CAD
Lovastatin vs. control
F/u at 1 year revealed IMT reduction of 0.031 mm; p<0.05
Koshiyama et al. (J. Card. Pharmacol.) compared amlodipine
to placebo (n=11 in each group) on IMT. In 6 months they
saw a 0.052mm reduction in A group (p<0.05)
Spacil et al. (Angiology) studied 21 adults with FH treated
with statins or fibrates.
F/u at 29 months showed decrease in IMT 0.83 to 0.68;
p<0.01; greater effect with fibrates
0
cGMP
NO
X
?
l-Arg
NOSNO
CYP450K+
Lumen Vascular Smooth MuscleEndothelium
Shear
BK
PGI2Ach
Ca++
AA
PLC
GTP
X
K+C
a GC
dilation
K+C
a
Ca++X
NADPH
oxidase
O2-
.
XX
O2-
.
EDHF EDHF
cholesterol
X
Interaction between NO and EDHF
EDHF pathway
cGMP
NO?
l-Arg
NOSNO
K+
Lumen Vascular Smooth MuscleEndothelium
Shear
BK
AchCa++
AA
PLA2
GTP
X
K+C
a GC
dilation
K+C
a
Ca++CYP450
(EET)
EDHF
COXPGI2 PGI2
AC cAMP
ATP
1
EDHF
Efficacy of Folic Acid as a Therapy for
Impaired Endothelial Function
Verhaar et al. (Circ 1999) In patients with FH, folic acid
restored normal endothelial function without lowering
cholesterol
Wilmink et al. (ATVB, 2000) showed that folic acid
prevented the acute reduction in FMD following a fat load
(whipped cream) in normal subjects
0
NOS isoformsNitric Oxide Synthase Isoforms
nNOS iNOS eNOS
(NOSI) (NOSII) (NOSIII)
Calcium dependent
Calmodulin dependent
Constitutively active
Caveolin sensitive
NO Production
Localization
Endothelium
Smooth muscle
Neurons
+ - +
+ + +
+ - +
+ - +
+ +++ +
+ + +++
+ +++ +
+++
Potential Mechanism of Folic Acid-
Improvement in Endothelial Function
Reduction in homocysteine levels – cofactor for MTHFR
(only in those with hyperhomocysteinemia)
Direct ROS scavenging effect
Increase BH4:BH2 ratio, thus increasing NO production
0
furchgottFirst Description of Endothelial-Dependent
Vasodilation
- Furchgott and Zawadzki, Nature 1980
• Rabbit aorta
• NE constriction
• Ach dilation
1
NO PGI2 schema
cGMP
NO?
l-Arg
NOSNO
Lumen Vascular Smooth MuscleEndothelium
Shear
BK
AchCa++
GTP
X
K+C
a GC
dilation
K+C
a
Ca++
Endothelial Nitric Oxide Synthase
cNOS
L-Arginine
citrulline
NO
BH4
Ca++
calmodulin
FAD
FMN
caveolin
caveolinCa++
calmodulin
3
NOS isoformsNitric Oxide Synthase Isoforms
nNOS iNOS eNOS
(NOSI) (NOSII) (NOSIII)
Calcium dependent
Calmodulin dependent
Constitutively active
Caveolin sensitive
NO Production
Localization
Endothelium
Smooth muscle
Neurons
+ - +
+ + +
+ - +
+ - +
+ +++ +
+ + +++
+ +++ +
+++
NO PGI2 schema
cGMP
NO?
l-Arg
NOSNO
K+
Lumen Vascular Smooth MuscleEndothelium
Shear
BK
AchCa++
AA
PLC
GTP
X
K+C
a GC
dilation
K+C
a
Ca++
EDHF EDHF
ACCOX
PGI2 PGI2
cAMP
ATP
2
Etiol of EDHFPossible Etiologies of EDHF
Potassium ions
Epoxyeicosatrienoic Acid
Hydrogen Peroxide
Nitric Oxide
Prostacyclin
Gap Junctions
EDHF pathway
cGMP
NO?
l-Arg
NOSNO
K+
Lumen Vascular Smooth MuscleEndothelium
Shear
BK
AchCa++
AA
PLC
GTP
X
K+C
a GC
dilation
K+C
a
Ca++CYP450
(EET)
EDHF
COXPGI2 PGI2
AC cAMP
ATP
1
EDHF
cGMP?
NO
X
l-Arg
NOSNO
CYP450K+
Lumen Vascular Smooth MuscleEndothelium
Shear
BK
PGI2Ach
Ca++
AA
PLC
GTP
X
K+Ca
GC
dilation
K+Ca
Ca++
X
NADPH
oxidase
O2
XX
O2
EDHF EDHF
Hypercholesterolemia
Diabetes
Smoking
K+Ca
H2O2SOD
EET
Is NO important?Is NO-mediated Vasodilation
Really Important?
- Vasospasm
- syndrome X
Atherosclerosis
2
- Traub et al. ATVB 1998
Endothelial Dysfunction Leads to Atherosclerosis
(Shear and Atherosclerosis)
Laminar shear Flow reversals
Brach analyzer
In Vivo Measurement of Endothelial Function
(Endo-PAT 2000)
Normal
Endothelial
Function
Abnormal
Endothelial
Function
l-arginine
NOSHSP 90 BH4
NO
x
ADMA
•
Mechanism of Reduced Vascular NOMechan. Reduce NO
O-2
Hypertension
tobacco
Hypercholesterolemia
Diabetes Mellitus
Risk Factor
-ONOO
(peroxynitrite)
x
Injury-glucose
-oxLDL
-mechanical (HTN)
Inflammatory
Response
lymphocytesplatelets
monocytes
Migration and transformation
intima
media
adventitia
Fully developed plaque
foam cellssubintimal thickening
fibroblast migration
Development of Atherosclerosisdevelop athero
4